In automotive engineering, automatic transmissions, in particular stepped fully automatic transmissions with hydrodynamic torque converter and planetary transmissions are used for power transmission beside manual variable-speed transmissions.
Such fully automatic stepped transmissions act as powershift transmissions without interruption of the tractive force, wherein the power flow is effected via planetary gearsets and the gear changes occur by coupling or releasing individual planetary gearset elements. The coupling of individual planetary gearset elements at present mostly is effected by means of multidisk clutches which, however, are constructionally complex and heavy as well as require an undesirably large installation space. Since the multidisk clutches must be designed for a maximum torque to be transmitted, many friction points or disks moreover are necessary for the torque transmission. Due to the numerous friction points, the undesired drag torques are quite high in the decoupled condition and have a disadvantageous effect on the transmission efficiency.
It is the object of the invention to create a switching device for an automatic motor vehicle transmission, which is constructed particularly compact, can be manufactured easily and at low cost and provides for a particularly high transmission efficiency.